Vehicle control system including token verification and code reset features

ABSTRACT

A control system for a vehicle includes a controller for learning a unique code of a token to define a learned token capable of causing performance of a function associated with the vehicle, for example. The controller performs remote token verification to generate an indication relating to whether a new uniquely coded token has been learned by the controller. The control system is advantageously used for a vehicle security system also enabling starting of the vehicle. The token may be a passive transponder. Token verification may also be incorporated in a remote keyless entry system, and a remote engine starting system, for example. In one embodiment, the token verification is based upon the controller being recently entered into the token learning mode. According to another embodiment, the token verification is based upon a number of learned tokens, a change in that number, or a change in a learned code of a token. The indication may be provided at the vehicle or remote therefrom by any of a light, a visual display, a vibration transducer, a speech message generator, and an audible signal generator, for example. A previous set of authorized token codes may be readily reset or restored to operate the system if unauthorized codes have been more recently added.

RELATED APPLICATION

The present application is a continuation-in-part application of U.S.patent application Ser. No. 08/622,515, filed Mar. 25, 1996 now pending,which, in turn, is a continuation-in-part of application Ser. No.08/423,570, filed Apr. 14, 1995 now U.S. Pat. No. 5,654,688.

FIELD OF THE INVENTION

The present invention relates to the field of control systems, and moreparticularly, to a control system for a vehicle.

BACKGROUND OF THE INVENTION

Vehicle security systems are widely used to deter vehicle theft, preventtheft of valuables from a vehicle, deter vandalism, and to protectvehicle owners and occupants. A typical automobile security system, forexample, includes a central processor or controller connected to aplurality of vehicle sensors. The sensors, for example, may detectopening of the trunk, hood, doors, windows, and also movement of thevehicle or within the vehicle. Ultrasonic and microwave motiondetectors, vibration sensors, sound discriminators, differentialpressure sensors, and switches may be used as sensors. In addition,radar sensors may be used to monitor the area proximate the vehicle.

The controller typically operates to give an alarm indication in theevent of triggering of a vehicle sensor. The alarm indication maytypically be a flashing of the lights and/or the sounding of the vehiclehorn or a siren. In addition, the vehicle fuel supply and/or ignitionpower may be selectively disabled based upon an alarm condition.

A typical security system also includes a receiver associated with thecontroller that cooperates with one or more remote transmitterstypically carried by the user as disclosed, for example, in U.S. Pat.No. 4,383,242 to Sassover et al. The remote transmitter may be used toarm and disarm the vehicle security system or provide other remotecontrol features from a predetermined range away from the vehicle.

Other vehicle security systems may be associated with the ignition ofthe vehicle. More particularly, one type of conventional vehiclesecurity system includes a passive transponder either carried by thekeychain or embedded in the ignition key. When the transponder ispositioned adjacent the ignition switch, the transponder is inductivelypowered and transmits a uniquely coded signal to a receiver in thevehicle. When a properly coded transponder is detected, the vehicleengine may be allowed to start, for example. In other words, an ignitionor fuel cutoff is normally operative to prevent the engine from startingor running, unless the proper transponder is sensed. Accordingly,vehicle security is increased.

The security system may have multiple transponders capable of disablingthe ignition or fuel cutoff to thereby permit operation of the vehicle.These uniquely coded transponders may be added or deleted from thevehicle controller. Unfortunately, the owner of the vehicle may not knowthat a transponder has been added without authorization.

U.S. Pat. No. 5,513,105 to Krones, for example, discloses a vehiclesecurity system including a so-called “computerized key” which sends aunique digitally encoded signal through a so-called “keyport” in thevehicle to a processor and controller in the vehicle. The vehiclestarting is interrupted unless the proper computerized key is presentedto the keyport. A valet mode is also possible wherein the computerizedkey is not needed. In addition, the system may be reprogrammed to acceptnew replacement keys. The processor and controller may be programmed toaccept and recognize authorization of a plurality of computerized keys,each having individual uniquely identifying digital numbers storedtherein. A program mode may be entered by presenting an authorized keyfor set time, then presenting new keys to be added. In the event thatthe memory has been filled, a long beep is indicated and the programmode is terminated. A lost key function permits a user to return thesystem to the program mode and thereby authorize a new set of keys tothe exclusion of the previously authorized keys. Entering the lost keymode involves disconnecting the vehicle battery for a set time.

U.S. Pat. No. 5,055,701 to Takeuchi discloses a keyless entry systemusing a random code portion to prevent code stealing. Along these lines,U.S. Pat. No. 4,928,098 to Dannhaeuser also discloses an electronic keywherein a new coinciding code is automatically set in the infraredtransmitter and receiver after each transmission and reception event.U.S. Pat. No. 5,563,579 to Carter discloses a security system for aplurality of cars, such as on a car dealer parking lot. A key storagebox is mounted to the vehicle window. The storage box also includes asensor for determining whose key is being used to unlock the box.

Unfortunately, conventional vehicle security systems using transpondershave tended to attempt to increase transponder security by adding randomor pseudorandom coding to the passive transponders. Unfortunately, asecurity threat still exists based upon unauthorized learning of auniquely coded transponder or other token, for example. Once such atransponder or token has been learned, the would-be thief can return tothe vehicle and defeat the security system.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of theinvention to provide a vehicle control system and related method forreducing the risk of an unauthorized token being able to operate thevehicle control system.

It is another object of the present invention to provide a system andmethod for reducing the risk of an unauthorized token being able tooperate the vehicle control system, and also permitting the owner toreadily return the system to the correct operating condition after anunauthorized token has been more recently learned.

These and other objects, features, and advantages in accordance with thepresent invention are provided by a vehicle function control systemincluding a token reader at the vehicle, and a controller at the vehiclefor controlling at least one vehicle function responsive to the tokenreader. The controller preferably includes token learning means forlearning the unique code of the token to define a learned token capableof controlling the vehicle function, and token verifying means forgenerating an indication relating to whether a new token has beenlearned by the token learning means to thereby alert the user of apotentially unauthorized token capable of controlling the vehiclefunction.

The token may include unique code generating means for generating aunique code signal. For example, the unique code generating means maygenerate an electrical, magnetic, or optical unique code signal. Thetoken may include a transmitter and unique code generating means forcausing the transmitter to generate a unique code signal, and whereinthe reader also comprises a receiver. In addition, token triggeringmeans may be provided for causing the token to transmit the unique coderesponsive to positioning the token adjacent a predetermined portion ofthe vehicle. In one embodiment, the transmitter comprises a passivetransponder, and the system further comprises transponder powering meansfor powering the passive transponder when same is positioned adjacent apredetermined portion of the vehicle. In one variation, the token ispositioned in or adjacent the vehicle ignition key.

Another aspect of the invention is that the controller may compriseengine enabling means for enabling operation of the vehicle engineresponsive to positioning of the learned token adjacent the ignitionswitch. In addition, the controller may include door unlocking means forunlocking of a vehicle door responsive to positioning of the at leastone learned token adjacent the vehicle.

The token learning means may be switchable between a learning modepermitting learning of at least one token, and a secure mode. In oneembodiment, the token learning means may include token deleting meansfor deleting all prior learned tokens based upon entering the learningmode.

The token verifying means may further include learning mode enteredindicating means for indicating that the learning mode of the tokenlearning means has been entered. The learning mode entered indicatingmeans may comprise time lapse means for indicating when the learningmode of the token learning means has last been entered. The time lapsemeans, in turn, may comprise means for progressively indicating apassage of time since the learning mode has last been entered.

Alternately, the token verifying means may include learned token numberindicating means for indicating a number of learned tokens. The tokenverifying means may also alternately include learned token changeindicating means for indicating a change in a number of learned tokensor means for generating an indication relating to whether a new tokenhas been learned by the token learning means. The verifying means mayfurther comprise activating means for causing the indicating means togenerate an indication.

Another aspect of the invention relates to the ease of returning thesystem to operate from a previous authorized set of tokens. According tothis aspect, the vehicle function control system preferably furtherincludes token code reset means for permitting the user to restore atleast one previously learned code and remove at least one more recentlylearned code. The token verifying means may enter a warning mode andremains in the warning mode for a predetermined warning time responsiveto a new uniquely coded token being learned. In addition, learned codesdesignated as current are capable of controlling at least one vehiclefunction, and codes designated hold are capable of being changed tocurrent. Thus, the token code reset means may include means for changingat least one code from current to hold responsive to learning a newuniquely coded token.

The token code reset means preferably further comprises means forlearning at least one new uniquely coded token as a temporary code whichis also capable of controlling at least one vehicle function. The tokencode reset means may also include means for deleting hold codes, andconverting temporary codes to current codes responsive to expiration ofthe predetermined warning time. In addition, the token code reset meansmay delete temporary codes and maintain hold codes responsive tolearning a new uniquely coded token when in the warning mode.

The token code reset means may include restore means for restoring holdcodes to current codes, and for deleting temporary codes responsive tolearning a new uniquely coded remote token matching a hold code and whenin the warning mode. Also, the restore means may cause exit from thewarning mode.

A method aspect of the invention is for controlling at least one vehiclefunction using at least one uniquely coded token for being carried by auser. The method preferably comprises the steps of: reading the token atthe vehicle; providing a controller at the vehicle for controlling atleast one vehicle function responsive to reading the token; learning theunique code of the at least one token into the controller to define alearned token capable of controlling the at least one vehicle function;and generating an indication relating to whether a new token has beenlearned into the controller to thereby alert the user of a potentiallyunauthorized token capable of controlling the at least one vehiclefunction. The method may also include the step of restoring at least onepreviously learned code and removing at least one more recently learnedcode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of the vehicle security systemaccording to the invention.

FIG. 2 is a schematic diagram of a remote transmitter for the vehiclesecurity system according to the invention.

FIG. 3 is a schematic diagram of a remote control vehicle securitysystem according to the present invention.

FIG. 4 is a schematic diagram of a vehicle control system including acoded transponder positioned in a token adjacent the ignition switchaccording to the invention.

FIG. 5 is a schematic diagram of a vehicle control system including acoded transponder positioned within the ignition key according to thepresent invention.

FIG. 6 is a schematic diagram of a vehicle control system including acode reader for a coded key according to the invention.

FIG. 7 is a schematic diagram of a vehicle control system including areader associated with vehicle door lock control and a token in the formof a card according to the invention.

FIGS. 8 and 9 are flow charts illustrating examples of remotetransmitter verification according to the invention.

FIG. 10 is a first flow chart illustrating a portion of the transmittercode reset feature in accordance with the present invention.

FIG. 11 is a second flow illustrating another portion of the transmittercode reset feature in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

Referring now to the schematic block diagram of FIG. 1, a vehiclesecurity system 10 according to one aspect of the invention is firstdescribed. The security system includes a controller 11 which, in turn,in the illustrated embodiment, includes a central processing unit ormicroprocessor 12 operating under stored program control.

In the illustrated embodiment, a transmitter and receiver 13 areconnected to the microprocessor 12 for receiving signals from a remotetransmitter and for transmitting signals to a remote unit, as will bedescribed in greater detail below. As would be readily understood bythose skilled in the art, the transmitter portion of the controller 11may not be needed in some embodiments of the invention. An antenna 13 ais illustratively connected to the transmitter and receiver 13.

In the illustrated embodiment, the microprocessor is also operativelyconnected to a memory (EEPROM) 14 and an input interface 15 and anoutput interface 16. As would be readily understood by those skilled inthe art, the microprocessor 12 may alternately or additionally have itsown on-board memory.

The input interface 15 is illustratively connected to various vehicleinput devices including: an ignition switch 20; a key in the ignitionsensor 21; two zone sensors 22 a, 22 b; conventional trunk hood and doorpin sensors or switches 23, 24, and 25, respectively; and door lockswitches 28. In addition, a pre-warn sensor 26 and valet switch 27 alsoprovide inputs to the controller 11 in the illustrated embodiment. Aswould be readily understood by those skilled in the art, other inputsare also contemplated by the present invention and are generallydescribed herein by the term sensor. In addition, an input signal mayalso be received from a remote transmitter 50 (FIG. 2).

The output interface 16 of the controller 11 may preferably be connectedto a plurality of output devices. As shown in FIG. 1, the outputs mayinclude auxiliary relay outputs 30, such as for window control, remotestarting, or a remote alarm indication, as would be readily understoodby those skilled in the art. A siren and/or lights 31, and green and redlight emitting diodes (LEDs) 32, 33 for dashboard mounting are alsoillustratively connected to the controller 11. Other outputs may bedirected to a valet LED 34, a dome light 36, a central lock relay orlock control unit 41, a starter kill circuit 42, and an armed relayoutput 43. In addition, other outputs may be directed to one or more ofan audible tone generator 37, an alphanumeric display 44, a speechmessage annunciator 45, and a vibration transducer 46, as will bereadily appreciated by those skilled in the art. Other similarindicating devices are also contemplated by the present invention, aswould be readily understood by those skilled in the art.

Referring now more particularly to FIG. 2, a remote transmitter 50 inaccordance with the invention is described. The remote transmitter 50includes a housing 51 and a plurality of first momentary contactswitches 52 a-52 d carried by the housing. A second momentary contactswitch 53 and an indicating light, such as the illustrated LED 54 arealso carried by or mounted on the housing 51. As would be readilyunderstood by those skilled in the art, the remote transmitter 50 istypically relatively small and includes an opening 55 for facilitatingconnection to a vehicle key ring, for example. In addition, the remotetransmitter 50 includes a central processing unit or microprocessor 56operatively connected to the plurality of first switches 52 a-52 d, thesecond switch 53, and the LED 54. The microprocessor is also connectedto a transmitter and/or receiver circuit 57 and its associated antenna57 a for transmitting and/or receiving signals to and from thecontroller 11 of the vehicle security system 10. Accordingly, the term“remote transmitter” is used broadly herein to describe the embodimentalso including receiver means.

The remote transmitter 50 may also include a numeric or alphanumericdisplay 58, and a speaker 59 coupled to an audible tone generator or aspeech message generator, as may be provided by the microprocessor 56. Avibration transducer, not shown, may also be incorporated into theremote transmitter 50 for communicating to the user as would be readilyunderstood by those skilled in the art.

The controller 11 preferably includes remote transmitter learning means47 for permitting the addition or learning of a coded remote transmitter50 to be capable of switching the controller between armed and disarmedmodes, for example. In the armed mode the controller 11 is capable ofgenerating an alarm via alarm indication means, such as the siren and/orflashing lights 31. The controller 11 generates the alarm responsive toat least one of the vehicle sensors, such as the trunk, hood and doorswitches 23, 24 and 25, or the other sensors 22 a, 22 b as would bereadily understood by those skilled in the art. In the disarmed mode thecontroller 11 does not generate an alarm responsive to one or more ofthe vehicle sensors so that the user may enter the vehicle, for example.

The controller 11 preferably comprises remote transmitter verifyingmeans 49 for generating an indication relating to whether a new uniquelycoded remote transmitter has been learned by the remote transmitterlearning means 47. In addition, the remote transmitter learning means 47is preferably switchable between a learning or program mode permittinglearning of a unique code of a remote transmitter 50, and a secure mode.As would be readily understood by those skilled in the art, the learningmode may be entered for a relatively short predetermined time and thenautomatically revert back to the secure mode to reduce the possibilityof unauthorized remote transmitters being learned.

In one embodiment, the remote transmitter verifying means 49 compriseslearning mode entered indicating means for indicating that the learningmode of the remote transmitter learning means has been entered. Moreparticularly, the learning mode entered indicating means preferablycomprises time lapse means for indicating when the learning mode of theremote transmitter learning means has last been entered. This indicationcan be provided by progressively indicating the elapsed time since thelearning mode has last been entered.

According to another approach or embodiment of the invention, the remotetransmitter verifying means 49 preferably comprises learned remotetransmitter number indicating means for indicating a number of learnedremote transmitters. In an embodiment where all remote transmitters aredeleted when a new one is learned, the number of learned transmittersmay change indicating that an unauthorized transmitter has been learned.Alternately, the remote transmitter verifying means 49 may compriselearned remote transmitter change indicating means for directlyindicating a change in a number of learned remote transmitters. In yetanother embodiment, the remote transmitter verifying means 49 preferablycomprises learned remote transmitter code change indicating means forindicating a change in a unique code of the learned remote transmitters.

The remote transmitter verifying means 49 preferably includes remotetransmitter indicating means for providing the indication. In otherwords, indicating means, such as a dashboard mounted light emittingdiode 32, 33, may be flashed a number of times corresponding to thenumber of coded remote transmitters in one embodiment. Accordingly, theuser is ensured that only the coded remote transmitters 50 under hiscontrol may operate the vehicle security system 10, and that no otherremote transmitters have been surreptitiously coded to operate thecontroller.

Other embodiments of remote transmitter indicating means include, forexample, the audible tone generator 37, numeric display 44, speechmessage generator 45 and vibration transducer 46 driven by thecontroller and associated with the vehicle. The dome light 36,headlights 31, and other LED's 32, 33 and 34 may also be used to give anindication to the user relating to the remote transmitters coded tooperate the controller 11.

The remote transmitter indicating means may also be associated with orcarried by a remote transmitter 50, or may be otherwise remote from thevehicle and be communicated to the remote site via a satellite orcellular telephone connection. For example, the indication means may beprovided by a light 54, an alphanumeric display 58, a speech or tonegenerator 59, and a vibration transducer, for example, carried by theremote transmitter 50 (FIG. 2). Alternately, a remote monitoring stationmay be provided to monitor one or a plurality of vehicles in cooperationwith the transmitter verifying means of each respective vehicle. Inaddition, a pager may be carried by the user to provide the indication.

The indication given to the user may preferably be the number of codedremote transmitters currently capable of switching the controller 11 tothe disarmed mode from the armed mode. Alternately, the indication maybe related to a change in the number of coded remote transmitters or achange in a code of a learned remote transmitter. The various indicatingmeans and remote transmitter verifying means may also be used to simplyalert the user that the learning mode has been recently entered.Accordingly, the remote transmitter verifying means 49 provides anindication relating to whether one or more remote transmitters has beenadded or learned without the owner's consent or knowledge. Theindicating means may also further comprise repeater means for repeatingan indication relating to the number of coded transmitters 50 for apredetermined time period or a predetermined number of repetitions.

Should the user determine that an unauthorized remote transmitter hasbeen added or learned to operate the controller 11, the controller inone embodiment also preferably includes remote transmitter deletingmeans 48 for permitting deletion of the newly added unauthorized remotetransmitter or all of the coded remote transmitters 50 capable ofswitching the controller between the armed and disarmed modes. In oneembodiment, the deleting means preferably comprises means for deletingall of the previously learned remote transmitters. All of the previouslylearned remote transmitters may be deleted based upon entering thelearning mode, that is, either when the learning mode is initiallyentered or when the first remote transmitter is learned, for example. Ifall of the coded remote transmitters are deleted by the deleting means48, the authorized transmitters may thereafter be added by the remotetransmitter learning means 47 as would be readily understood by thoseskilled in the art. As described in greater detail below, in anotherembodiment, transmitter code reset means may be provided to remove anewly learned code and restore a previously learned code.

The vehicle security system 10 also preferably includes activating meansfor activating the remote transmitter indicating means responsive to apredetermined condition. For example, the indicating means may betriggered by the activating means responsive to operation of one of asignal from the remote transmitter 50; a manually operable switch, suchas the valet switch 27; an ignition switch 20, including a key in theswitch sensor 21; a door position switch 25; and a door lock switch 28.For example, the valet switch, ignition switch, remote transmitterbuttons, or other manual switches could be operated in a predeterminedsequence to activate the indicating means. Other similar means foractivating the indicating means are also contemplated by the invention,and will be readily appreciated by those skilled in the art.

Referring now additionally to FIGS. 3-7, various embodiments of thetoken verification feature of the present invention are furtherdescribed. Of course, in some embodiments described herein the tokenincludes a transmitter, and hence the same principles and features applyas described above for the remote transmitter verification feature.

A vehicle security system 10 is schematically illustrated in FIG. 3including the controller 11 along with the siren 31 and door switches25. The transmitter verifying means 49 is illustrated in a separateblock for clarity, although those of skill in the art will recognizethat the logic features of the transmitter verifying means may bereadily implemented via the microprocessor of the controller. Twoillustrated remote transmitters 50 are capable of switching thecontroller 11 between armed and disarmed modes. When in the armed mode,tripping of the vehicle door switches 25 may typically activate thesiren 31. In addition, the door switches 25 may also be used as part ofthe activation means to cause the transmitter verifying means to give anindication relating to an unauthorized remote transmitter.

Referring now more particularly to FIG. 5, an engine start or run enablevehicle security system 80 is illustrated as another example of theremote transmitter verification aspect of the present invention appliedto a token. In other words, a token may be uniquely coded. Moreover, aplurality of such tokens may be individually coded. The token isillustratively in the form of a passive transponder 81 which includes apower receiver 82 for capturing radiated power from the powertransmitter 83 positioned adjacent the ignition switch 84. In theillustrated embodiment, the ignition switch 84 still receives aconventional key 85, although those of skill in the art will appreciatethat in other embodiments, the transponder 81 by itself may enablestarting and running of the engine, as well as unlock the steering wheelwithout requiring a separate mechanical key.

When the transponder 81 is brought sufficiently close to the ignitionswitch 84, it receives enough power to supply the coded transmitter 86which, in turn, transmits a coded signal to the illustrated codereceiver 87. The enable controller 88 includes the illustrated tokenverification means 89 which operates as described above for the uniquelycoded remote transmitters. In addition, the enable controller 84 alsoincludes the token code reset means 90 which as will be describedfurther below, permits the user to readily reactivate or resetpreviously learned codes and delete new codes which may have beensurreptitiously added. The token verification means 89 may give anindication via any of the approaches as described above for the remotetransmitter verification means and needs no further description herein.

The embodiment of the vehicle security system 80′ shown in FIG. 5includes the power receiver 82′ and the code transmitter 86′ embedded inthe key 85′. The other components include similar reference numerals tothe components described above with reference to FIG. 4. Accordingly,these components need no further description. In other words, in thisembodiment, the key 85′ serves as the uniquely coded token carried bythe user, rather than the separate passive transponder 81 as in FIG. 4.

Turning now to FIG. 6 another variation of the engine start and runenable vehicle security system 95 associated with a vehicle ignitionswitch 99 is now described. In this system 95 the key 96 includes anembedded readable portion 97. Those of skill in the art will appreciatethat the embedded readable portion 97 may include a particularelectrical resistance, a magnetic element, an optical element, anintegrated circuit, or any other similar device capable of generating inthe associated reader 98 a uniquely coded signal. Again, in this system95, the key 96 serves as the token which is read to enable the vehicleto be started and driven. In addition, the vehicle security system 95includes an enable controller 100 which also includes the illustratedtoken verification means 101 and the token code reset means 102. Ofcourse, as will be readily appreciated by those skilled in the art, thecode generating element or portion 97 need not be carried by theillustrated key 96, but can be carried by a substrate, such as a plasticcard, or in any device which is customarily kept in the user'spossession so as enable the user to operate the vehicle.

Expanding these concepts of token verification and token code reset,FIG. 7 shows their implementation in a vehicle security system 103 foroperating the vehicle door locks. More particularly, a reader 104 ismounted at a location on the vehicle, such as near the door handle, forexample. The reader 104, may be of any type, such as optical, magnetic,electrical, etc. as will be readily appreciated by those skilled in theart. In the illustrated embodiment, the token is provided in the form ofa plastic card 105. The card 105 carries an embedded code generatingelement 106. The code generating element 106 cooperates with the reader104 when brought into proximity or contact therewith to generate aunique code for the card 105. As a further example, the card 105 mayhave an embedded integrated circuit therein to communicate with thereader 104 along the lines of a so-called “smart card” as will bereadily appreciated by those skilled in the art. The reader 104 isoperatively connected to the schematically illustrated door lockcontroller 107.

The door lock controller 107 includes the token verification means 108and token code reset means 109. The token verification means 108 hasbeen described already and will be further described below. The tokencode reset means 109 will also be further described below. In short, thetoken verification alerts the user that an unauthorized token may havebeen learned into the system, while the token code reset provides theuser with a convenient way to reinstate the previous token codes. Thoseof skill in the art will appreciate other vehicle related controlfeatures that are contemplated by the present invention in addition toengine starting and door lock control.

Returning now again to the concept of remote transmitter verification. Amethod aspect in accordance with the present invention is for increasingsecurity in permitting remote control of a function associated with avehicle and using at least one uniquely coded remote transmitter 50, anda receiver 13 within the vehicle for receiving a signal from theuniquely coded remote transmitter. The method preferably comprises thesteps of: storing in a memory 14 a unique code of a remote transmitter50 to define a learned remote transmitter capable of causing performanceof a function associated with the vehicle, and generating an indicationrelating to whether a new uniquely coded remote transmitter has beenstored in the memory to thereby alert the user of a potentiallyunauthorized learned remote transmitter capable of remotely performingthe function associated with the vehicle.

A particular example of the transmitter verification feature of thepresent invention is explained with further reference to the flow chartof FIG. 8. In this example, the vehicle security system controller 11(FIGS. 1 and 3) preferably includes ignition switch monitoring means 20(FIG. 1) for determining whether a vehicle ignition switch is in an offposition or an on position as monitored at Block 61 and when thecontroller is in the disarmed mode (Block 60). If the ignition isswitched on (Block 63), the number of coded remote transmitters 50(FIGS. 1-3) is determined or verified (Block 65). The controller 11 alsopreferably includes activating means for activating an LED 32, 33(FIG. 1) to indicate the number of coded transmitters 50 at Block 67responsive to turning the vehicle ignition to the on position and whenthe controller 11 is in the disarmed mode. The number of codedtransmitters 50 may be repeated for a predetermined time, such as tenseconds, at Block 68. The verification feature is then stopped (Block69). If unsure, the driver could turn the ignition off, and then back tothe on position, to again verify the number of coded remote transmitters50. Those of skill in the art will readily appreciate alternateembodiments incorporating other indicating means or activating means asdescribed in greater detail herein. This same procedure or an equivalentthereto, can also be used to verify and indicate the tokens uniquelycoded to operate a control system as shown in FIGS. 4-7 in accordancewith the present invention.

Referring to the flow chart of FIG. 9, another variation of operation ofthe vehicle security system 10 is now explained. From the start (Block110), the door position is monitored at Block 112. If a door, such asthe driver's door, has been determined at Block 114 to have been openedand closed, it is next determined whether the remote transmitter learnmode has been entered or a remote transmitter code changed at Block 116.If the door has not been opened and closed, or the learn mode ortransmitter code not changed, the system returns to monitoring the doorposition at Block 112.

If the learn mode has been entered or the code changed, the elapsed timet since that event is compared against a threshold T1 at Block 118. Ifthe elapsed time t is less that T1, then a first duration signal may begenerated at Block 120. If the elapsed time t is between T1 and a secondthreshold T2 as determined at Block 122, then a second durationindication can be generated (Block 124). Similarly, if the elapsed timet is between T2 and a third threshold T3 as determined at Block 126,then a third duration indication may be given at Block 128. The sequencecan be extended or shortened as would be readily appreciated by thoseskilled in the art.

For example, if the learn mode has been entered within the priorforty-eight hours, an indicating light may be illuminated for a thirtysecond duration responsive to the activation means. The duration couldthereafter be decremented five seconds for each 48 hours of elapsedtime, so that the indication would eventually automatically terminatewith the passage of sufficient time. As another example, the light couldbe illuminated for ninety seconds the first day, and decrement tenseconds each day thereafter. It is desirable that the indication informthe user of how recently the learn mode or transmitter change has beenmade so that the user may correlate the change with someone's ability toaccess the system. An appropriate voice message could also be generatedalerting the user to when the learning mode was last entered, forexample. Again, this variation of verification and indication for acoded remote transmitter may be directly applicable and used with thetoken verification and indication as shown in FIGS. 4-7 as will bereadily appreciated by those skilled in the art.

Another aspect of the invention relates to the transmitter code resetmeans which permits the user to restore at least one previously learnedcode and remove at least one more recently learned code. The remotetransmitter verifying means may enter a warning mode and remain in thewarning mode for a predetermined warning time responsive to a newuniquely coded remote transmitter being learned. In addition, thelearned codes designated as current are capable of switching the alarmcontroller, for a vehicle security system, for example, and the codesdesignated hold are capable of being changed to current. Accordingly,the transmitter code reset means preferably comprises means for changingat least one code from current to hold responsive to learning a newuniquely coded transmitter.

The transmitter code reset means may further comprise means for learningat least one new uniquely coded transmitter as a temporary code which isalso capable of switching the alarm controller. The transmitter codereset means may further include means for deleting hold codes, andconverting temporary codes to current codes responsive to expiration ofthe predetermined warning time. Also, the transmitter code reset meansmay delete temporary codes and maintaining hold codes responsive tolearning a new uniquely coded transmitter when in the warning mode.

The transmitter code reset means may also include restore means forrestoring hold codes to current codes, and for deleting temporary codesresponsive to learning a new uniquely coded remote transmitter matchinga hold code and when in the warning mode. The restore means may alsofurther comprise means for exiting the warning mode.

The various means associated with the transmitter code reset feature maybe readily implemented using the processor of the controller, forexample, or may be implemented using conventional logic and signalprocessing circuitry as will be readily appreciated by those skilled inthe art. In addition, transmitter code reset means may be used in remotestarting, remote keyless entry and other similar applications as willalso be readily appreciated by those skilled in the art.

Turning now additionally to the flow chart of FIG. 10 operation of thetransmitter code reset function of the present invention is furtherdescribed. From the start (Block 140), the user may enter the controllerinto the transmitter learning mode at Block 146. Entry into the learningmode has been described above, however, those of skill in the art willappreciate that there are many other equivalent techniques to cause thecontroller to enter the transmitter learning mode.

Once in the learning mode, it is determined at Block 146 whether a newtransmitter code has been received. If a code is received, then at Block148 it is determined whether the 48 hour Automatic TransmitterVerification (ATV) warning period as described above is still inprogress. Of course the time could be changed to any suitable valuedepending on the application. If the controller is not currently in theATV warning period, then the ATV warning period is started at Block 150,and remote transmitter codes are moved from a current file to a holdfile. As would be readily appreciated by those skilled in the art, thecodes may not necessarily be transferred to another portion of memory,for example, rather a designation for the code may simply be updated.

At Block 160, the controller learns the newly received transmitter codesto a so-called temporary file. The newly learned transmitter codesremain in the temporary file or keep their temporary designation and areused to operate the controller upon exit from the learning mode (Block162) as will be readily appreciated by those skilled in the art.

Turning now briefly to the upper right-hand portion of FIG. 10, at Block164 it is determined whether the ATV warning period has expired. If so,the transmitter codes in the hold file are deleted, and the transmittercodes in the temporary file are moved to the current file. In otherwords, once the ATV warning period expires, the hold file contents aredeleted and the temporary codes become the current codes. The currentcode operate the controller until the learning mode is again entered.

If during the learning mode, the ATV warning period was already activeas determined at Block 148, the hold file contents are maintained (Block154). In addition, the transmitter codes in the temporary file aredeleted at Block 156. Accordingly, this defeats the would-be thief fromentering the learning mode several times without the user's knowledge.In other words, the codes in the hold file should be those previouslyauthorized by the user.

At Block 158 the ATV warning period may be restarted. Thereafter, thecontroller learns the new transmitter codes into the temporary file(Block 160), and the system operates with the new temporary codes uponexit from the learning mode (Block 162).

Turning now additionally to the flow chart of FIG. 11, a method forreturning the proper transmitter codes to operate the system and todelete any unauthorized codes is explained. The user desires bothsecurity and convenience. From the start (Block 170), if the system isstill in the ATV warning period as determined at Block 172, then theuser may toggle the ignition switch on and off two times within 5seconds (Block 174). The user may then transmit a code from atransmitter in his possession, and if the ignition is on, and wastoggled within the last 5 seconds, then the system will compare thereceived code with the hold file codes (Block 178).

If the just received code matches a code in the hold file, then thecodes in the temporary file are deleted at Block 180. This removes thetemporary codes that may have been surreptitiously added by a would-bethief. In addition, the transmitter codes from the hold file are thenmoved to the current file (Block 182). This restores the user's previousauthorized hold codes to operate the system. The ATV warning is turnedoff at Block 184, and the siren may be chirped at Block 186, beforestopping (Block 188), to thereby provide the user with confirmation thatthe codes from the temporary file have been deleted, and the codes fromthe hold file have been re-activated or changed to the currentdesignation or file.

Of course, the token code reset features and functions may be the sameor equivalent to those described for the remote transmitter code resetmeans. Accordingly, the flow charts for the remote transmitter codereset are applicable to the token code reset features as will be readilyappreciated by those skilled in the art. Accordingly, the token codereset means may also provide the ability for the user to reset a priorgroup of token codes once alerted by the token verification features.

Further information relating to the vehicle security system and aspectsthereof may be found in parent patent U.S. Pat. No. 5,654,688, assignedto the assignee of the present invention and incorporated herein byreference in its entirety. In addition, many modifications and otherembodiments of the invention will come to the mind of one skilled in theart having the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments disclosed, and that modifications and embodiments areintended to be included within the scope of the appended claims.

That which is claimed is:
 1. A vehicle function control systemcomprising: at least one uniquely coded token for being carried by auser and comprising at least one first electrical conductor; a tokenreader at the vehicle comprising at least one second electricalconductor for connecting to the at least one first electrical conductorof said at least one uniquely coded token and for reading the uniquecode therefrom; and a controller at the vehicle for controlling at leastone vehicle function responsive to said token reader, said controllercomprising token learning means for learning the unique code of said atleast one uniquely coded token to define at least one learned uniquelycoded token for controlling the at least one vehicle function, and tokenverifying means for generating an indication relating to whether a newuniquely coded token has been learned by said token learning means tothereby alert the user of a potentially unauthorized learned uniquelycoded token.
 2. A vehicle function control system according to claim 1further comprising token triggering means for causing said at least onetoken to transmit the unique code signal responsive to positioning saidat least one token adjacent a predetermined portion of the vehicle.
 3. Avehicle function control system according to claim 1 wherein saidtransmitter comprises a passive transponder.
 4. A vehicle functioncontrol system according to claim 3 further comprising transponderpowering means for powering said passive transponder when same ispositioned adjacent a predetermined portion of the vehicle.
 5. A vehiclefunction control system according to claim 1 further comprising avehicle ignition key; and wherein said at least one token is positionedin or adjacent the vehicle ignition key.
 6. A vehicle function controlsystem according to claim 5 wherein said controller comprises engineenabling means for enabling operation of the vehicle engine responsiveto positioning of the at least one learned token adjacent the ignitionswitch.
 7. A vehicle function control system according to claim 1wherein said controller comprises door unlock means for unlocking atleast one vehicle door responsive to positioning of the at least onelearned token adjacent the vehicle.
 8. A vehicle function control systemaccording to claim 1 wherein said token learning means is switchablebetween a learning mode permitting learning of the unique code of saidat least one token, and a secure mode.
 9. A vehicle function controlsystem according to claim 8 wherein said token learning means comprisestoken deleting means for deleting the unique codes of all prior learnedtokens based upon entering the learning mode.
 10. A vehicle functioncontrol system according to claim 8 wherein said token verifying meanscomprises learning mode entered indicating means for indicating that thelearning mode of said token learning means has been entered.
 11. Avehicle function control system according to claim 10 wherein saidlearning mode entered indicating means comprises time lapse means forindicating when the learning mode of said token learning means has lastbeen entered.
 12. A vehicle function control system according to claim11 wherein said time lapse means comprises means for progressivelyindicating a passage of time since the learning mode has last beenentered.
 13. A vehicle function control system according to claim 1wherein said token verifying means comprises learned token numberindicating means for indicating a number of learned tokens.
 14. Avehicle function control system according to claim 1 wherein said tokenverifying means comprises learned token change indicating means forindicating a change in a number of learned tokens.
 15. A vehiclefunction control system according to claim 1 wherein said tokenverifying means comprises indicating means for generating an indicationrelating to whether a new token has been learned by the token learningmeans.
 16. A vehicle function control system according to claim 15wherein said indicating means comprises vehicle indicating meansassociated with the vehicle; and wherein said vehicle indicating meanscomprises at least one of a light, a visual display, a vibrationtransducer, a speech message generator, and an audible signal generator.17. A vehicle function control system according to claim 15 wherein saidindicating means comprises remote indicating means remotely positionedfrom the vehicle; and wherein said remote indicating means comprises atleast one of a light, a visual display, a vibration transducer, a speechmessage generator, and an audible signal generator.
 18. A vehiclefunction control system according to claim 15 wherein said verifyingmeans further comprises activating means for causing said indicatingmeans to generate an indication.
 19. A vehicle function control systemaccording to claim 18 wherein said activating means comprises anignition switch.
 20. A vehicle function control system according toclaim 18 wherein said activating means comprises vehicle activatingmeans associated with the vehicle; and wherein said vehicle activatingmeans comprises at least one of a manually operated switch, a vehicleswitch, and a vehicle sensor.
 21. A vehicle function control systemaccording to claim 18 wherein said activating means comprises remoteactivating means remote from the vehicle.
 22. A vehicle function controlsystem according to claim 1 further comprising token code reset meansfor permitting the user to restore at least one previously learned codeand remove at least one more recently learned code.
 23. A vehiclefunction control system according to claim 22 wherein said tokenverifying means enters a warning mode and remains in the warning modefor a predetermined warning time responsive to a new uniquely codedtoken being learned.
 24. A vehicle function control system according toclaim 23 wherein learned codes designated as current are for controllingat least one vehicle function; wherein codes designated hold arechangeable to current; and wherein said token code reset means comprisesmeans for changing at least one code from current to hold responsive tolearning a new uniquely coded token.
 25. A vehicle function controlsystem according to claim 24 wherein said token code reset means furthercomprises means for learning at least one new uniquely coded token as atemporary code which is also for controlling at least one vehiclefunction.
 26. A vehicle function control system according to claim 25wherein said token code reset means further comprises means for deletinghold codes, and converting temporary codes to current codes responsiveto expiration of the predetermined warning time.
 27. A vehicle functioncontrol system according to claim 26 wherein said token code reset meanscomprises means for deleting temporary codes and maintaining hold codesresponsive to learning a new uniquely coded token when in the warningmode.
 28. A vehicle function control system according to claim 27wherein said token code reset means further comprises restore means forrestoring hold codes to current codes, and for deleting temporary codesresponsive to learning a new uniquely coded token matching a hold codeand when in the warning mode.
 29. A vehicle function control systemaccording to claim 28 wherein said restore means further comprises meansfor exiting the warning mode.
 30. A vehicle function control systemresponsive to at least one uniquely coded token for being carried by auser, the vehicle function control system comprising: a token reader atthe vehicle; and a controller at the vehicle for controlling at leastone vehicle function responsive to said token reader, said controllercomprising token learning means for learning the unique code of the atleast one token to define at least one learned token for controlling theat least one vehicle function, and token verifying means for generatingan indication relating to whether a new token has been learned by saidtoken learning means to thereby alert the user of a potentiallyunauthorized learned token.
 31. A vehicle function control systemaccording to claim 30 wherein said token comprises unique codegenerating means for generating a unique code signal.
 32. A vehiclefunction control system according to claim 31 wherein said unique codegenerating means comprises means for generating at least one of anelectrical, magnetic, and optical unique code signal.
 33. A vehiclefunction control system according to claim 30 wherein said tokencomprises a transmitter and unique code generating means for causingsaid transmitter to generate a unique code signal; and wherein saidreader comprises a receiver.
 34. A vehicle function control systemaccording to claim 33 further comprising token triggering means forcausing said at least one token to transmit the unique code responsiveto positioning said at least one token adjacent a predetermined portionof the vehicle.
 35. A vehicle function control system according to claim33 wherein said transmitter comprises a passive transponder.
 36. Avehicle function control system according to claim 35 further comprisingtransponder powering means for powering said passive transponder whensame is positioned adjacent a predetermined portion of the vehicle. 37.A vehicle function control system according to claim 30 furthercomprising a vehicle ignition key; and wherein said token is positionedin or adjacent the vehicle ignition key.
 38. A vehicle function controlsystem according to claim 30 wherein said controller comprises engineenabling means for enabling operation of the vehicle engine responsiveto positioning of the learned token adjacent the ignition switch.
 39. Avehicle function control system according to claim 30 wherein saidcontroller comprises door unlocking means for unlocking of a vehicledoor responsive to positioning of the at least one learned tokenadjacent the vehicle.
 40. A vehicle function control system according toclaim 30 wherein said token learning means is switchable between alearning mode permitting learning of at least one token, and a securemode.
 41. A vehicle function control system according to claim 40wherein said token learning means comprises token deleting means fordeleting all prior learned tokens based upon entering the learning mode.42. A vehicle function control system according to claim 40 wherein saidtoken verifying means comprises learning mode entered indicating meansfor indicating that the learning mode of said token learning means hasbeen entered.
 43. A vehicle function control system according to claim42 wherein said token verifying means comprises learned token numberindicating means for indicating a number of learned tokens.
 44. Avehicle function control system according to claim 42 wherein said tokenverifying means comprises learned token change indicating means forindicating a change in a number of learned tokens.
 45. A vehiclefunction control system according to claim 42 wherein said tokenverifying means comprises indicating means for generating an indicationrelating to whether a new token has been learned by the token learningmeans.
 46. A vehicle function control system according to claim 42wherein said verifying means further comprises activating means forcausing said indicating means to generate an indication.
 47. A vehiclefunction control system according to claim 40 wherein said learning modeentered indicating means comprises time lapse means for indicating whenthe learning mode of said token learning means has last been entered.48. A vehicle function control system according to claim 47 wherein saidtime lapse means comprises means for progressively indicating a passageof time since the learning mode has last been entered.
 49. A vehiclefunction control system according to claim 30 further comprising tokencode reset means for permitting the user to restore at least onepreviously learned code and remove at least one more recently learnedcode.
 50. A vehicle function control system according to claim 49wherein said token verifying means enters a warning mode and remains inthe warning mode for a predetermined warning time responsive to a newuniquely coded token being learned.
 51. A vehicle function controlsystem according to claim 50 wherein learned codes designated as currentare for controlling at least one vehicle function; wherein codesdesignated hold are changeable to current; and wherein said token codereset means comprises means for changing at least one code from currentto hold responsive to learning a new uniquely coded token.
 52. A vehiclefunction control system according to claim 51 wherein said token codereset means further comprises means for learning at least one newuniquely coded token as a temporary code which is also for controllingat least one vehicle function.
 53. A vehicle function control systemaccording to claim 52 wherein said token code reset means furthercomprises means for deleting hold codes, and converting temporary codesto current codes responsive to expiration of the predetermined warningtime.
 54. A vehicle function control system according to claim 53wherein said token code reset means comprises means for deletingtemporary codes and maintaining hold codes responsive to learning a newuniquely coded token when in the warning mode.
 55. A vehicle functioncontrol system according to claim 54 wherein said token code reset meansfurther comprises restore means for restoring hold codes to currentcodes, and for deleting temporary codes responsive to learning a newuniquely coded token matching a hold code and when in the warning mode.56. A vehicle function control system according to claim 55 wherein saidrestore means further comprises means for exiting the warning mode. 57.A vehicle function control system responsive to at least one uniquelycoded token for being carried by a user, the vehicle function controlsystem comprising: a token reader at the vehicle; and a controller atthe vehicle for controlling at least one vehicle function responsive tosaid token reader, said controller comprising token learning means forlearning the unique code of the at least one token to define at leastone learned token for controlling the at least one vehicle function,token verifying means for generating an indication relating to whether anew token has been learned by said token learning means to thereby alertthe user of a potentially unauthorized learned token, and token codereset means for permitting the user to restore at least one previouslylearned code and remove at least one more recently learned code.
 58. Avehicle function control system according to claim 57 wherein said tokenverifying means enters a warning mode and remains in the warning modefor a predetermined warning time responsive to a new uniquely codedtoken being learned.
 59. A vehicle function control system according toclaim 58 wherein learned codes designated as current are for controllingat least one vehicle function; wherein codes designated hold arechangeable to current; and wherein said token code reset means comprisesmeans for changing at least one code from current to hold responsive tolearning a new uniquely coded token.
 60. A vehicle function controlsystem according to claim 59 wherein said token code reset means furthercomprises means for learning at least one new uniquely coded token as atemporary code which is also for controlling at least one vehiclefunction.
 61. A vehicle function control system according to claim 60wherein said token code reset means further comprises means for deletinghold codes, and converting temporary codes to current codes responsiveto expiration of the predetermined warning time.
 62. A vehicle functioncontrol system according to claim 61 wherein said token code reset meanscomprises means for deleting temporary codes and maintaining hold codesresponsive to learning a new uniquely coded token when in the warningmode.
 63. A vehicle function control system according to claim 62wherein said token code reset means further comprises restore means forrestoring hold codes to current codes, and for deleting temporary codesresponsive to learning a new uniquely coded token matching a hold codeand when in the warning mode.
 64. A vehicle function control systemaccording to claim 63 wherein said restore means further comprises meansfor exiting the warning mode.
 65. A vehicle function control systemaccording to claim 57 wherein said token comprises unique codegenerating means for generating a unique code signal.
 66. A vehiclefunction control system according to claim 65 wherein said unique codegenerating means comprises means for generating at least one of anelectrical, magnetic, and optical unique code signal.
 67. A vehiclefunction control system according to claim 57 wherein said tokencomprises a transmitter and unique code generating means for causingsaid transmitter to generate a unique code signal; and wherein saidreader comprises a receiver.
 68. A vehicle function control systemaccording to claim 67 further comprising token triggering means forcausing said at least one token to transmit the unique code responsiveto positioning said at least one token adjacent a predetermined portionof the vehicle.
 69. A vehicle function control system according to claim67 wherein said transmitter comprises a passive transponder.
 70. Avehicle function control system according to claim 69 further comprisingtransponder powering means for powering said passive transponder whensame is positioned adjacent a predetermined portion of the vehicle. 71.A method for controlling at least one vehicle function using at leastone uniquely coded token for being carried by a user, the methodcomprising: reading the token at the vehicle; providing a controller atthe vehicle for controlling at least one vehicle function responsive toreading the token; learning the unique code of the at least one tokeninto the controller to define a learned token for controlling the atleast one vehicle function; and generating an indication relating towhether a new token has been learned into the controller to therebyalert the user of a potentially unauthorized learned token.
 72. A methodaccording to claim 71 wherein the token comprises unique code generatingmeans for generating a unique code signal; and wherein the step ofreading the token comprises reading at least one of an electrical,magnetic, and optical signal from the at least one token.
 73. A methodaccording to claim 71 wherein the token comprises a transmitter andunique code generating means for causing the transmitter to generate aunique code signal; and wherein the step of reading the at least onetoken comprises receiving the unique code signal transmitted from the atleast one token.
 74. A method according to claim 73 further comprisingthe step of causing the at least one token to transmit the unique coderesponsive to positioning the at least one token adjacent apredetermined portion of the vehicle.
 75. A method according to claim 73wherein the transmitter comprises a passive transponder; and furthercomprising the step of powering the passive transponder when same ispositioned adjacent a predetermined portion of the vehicle.
 76. A methodaccording to claim 71 further comprising the step of enabling operationof the vehicle engine responsive to positioning of the learned tokenadjacent the ignition switch.
 77. A method according to claim 71 furthercomprising the step of unlocking at least one vehicle door responsive topositioning of the learned token adjacent the vehicle.
 78. A methodaccording to claim 71 further comprising the step of deleting all priorlearned tokens based upon entering a learning mode of the controller.79. A method according to claim 71 wherein the step of verifyingcomprises the step of indicating that the learning mode has beenentered.
 80. A method according to claim 71 wherein the step ofverifying comprises the step of indicating a number of learned tokens.81. A method according to claim 71 wherein the step of verifyingcomprises the step of indicating a change in a number of learned tokens.82. A method according to claim 71 wherein the step of verifyingcomprises the step of generating an indication relating to whether a newtoken has been learned by the token learning means.
 83. A methodaccording to claim 71 further comprising the step of restoring at leastone previously learned code and removing at least one more recentlylearned code.
 84. A method according to claim 83 wherein the restoringand removing step comprises entering a warning mode and remaining in thewarning mode for a predetermined warning time responsive to a newuniquely coded token being learned.
 85. A method according to claim 84wherein learned codes designated as current are for controlling the atleast one vehicle function; wherein codes designated hold are changeableto current; and wherein the step of restoring and removing compriseschanging at least one code from current to hold responsive to learning anew uniquely coded token.
 86. A method according to claim 85 wherein thestep of restoring and removing comprises learning at least one newuniquely coded token as a temporary code which is also controlling theat least one vehicle function.
 87. A method according to claim 86wherein the step of restoring and removing comprises deleting holdcodes, and converting temporary codes to current codes responsive toexpiration of the predetermined warning time.
 88. A method according toclaim 87 wherein the step of restoring and removing comprises deletingtemporary codes and maintaining hold codes responsive to learning a newuniquely coded token when in the warning mode.
 89. A method according toclaim 88 wherein the step of restoring and removing comprises restoringhold codes to current codes, and for deleting temporary codes responsiveto learning a new uniquely coded token matching a hold code and when inthe warning mode.
 90. A method according to claim 89 wherein the step ofrestoring and removing further comprises exiting the warning mode.